Prior art height adjustable supports or legs are unsuited for applications described herein in that they are constructed to adjust an individual leg to a number of height positions by having holes mounted at several heights in the inner leg, or in the inner and outer leg opposite each other, through which a pin can be stuck at the desired height or the outer leg contains a spring-based locking means which is intended for engaging a complementary locking means mounted in the inner leg. Although such systems function adequately, they do not provide an adequate and safe design for use in children's adjustable height play tables.